Abnormal Cardiovascular Responses During Orthostatic Hypotension in Cardiac Amyloidosis Revealed by Semi-Sitting/Standing Stress Echocardiography.

BACKGROUND: Mechanisms of orthostatic hypotension (OH) in cardiac amyloidosis (CA) patients remain largely unclarified. CASE SUMMARY: We performed semi-sitting/standing stress echocardiography in 6 healthy volunteers, 5 patients with CA but without OH [CA/OH(-)], and 4 with CA and OH [CA/OH(+)]. Semi-sitting/standing stress echocardiography revealed broad abnormal responses during semi-sitting/standing in CA/OH(+) patients, including reduced increase in heart rate, reduction in blood pressure, lack of reduction in left ventricular end-systolic dimension (contractile reserve), severely reduced stroke volume/cardiac output, paradoxical reduction in systemic vascular resistance, and paradoxical dilation of inferior vena cava dimension, compared to the group oh healthy volun. DISCUSSION: These findings may suggest a combined and broad abnormal compensations of all chronotropy, left ventricle, arteries, and veins during semi-sitting/standing, leading to severe OH with CA. TAKE-HOME MESSAGES: Broad cardiovascular abnormalities were observed in 4 patients with CA and OH. Semi-sitting/standing stress echocardiography may hold potential for exploring the underlying pathophysiological mechanisms.